Basic Trope: A character takes a seemingly fatal amount of damage, yet survives.
Alice beats Emperor Evulz, then throws him off a cliff and drowns him. He shows up a few episodes later, ready for revenge.
Alice has a heart attack in one episode. In the next, she's alive and well.
Alice beats Emperor Evulz, then throws him off a cliff, drowns him, and orders a tactical airstrike over that part of the sea. She then orders a giant fishing boat to fish those waters clean and freeze everything they catch. However, despite all this, Emperor Evulz still comes back.
However, after a few months, he comes back, explaining that he only survived because he put himself into a temporary death state to survive her onslaught of attacks.
...An impostor hired by the real Emperor Evulz, who's still in intensive care from his not quite fatal wounds.
...which turns out to be Alice in disguise.
Emperor Evulz has an overly long "death" animation.
Alice has a heart attack in one episode. In the next, a funeral is held for her, but the people who attend hear her scream "SURPRISE!" when she wakes up inside her coffin.
Alice is expecting Emperor Evulz to return at any moment. And after a while, he does. However, as soon as he appears and explains to Alice how he's still alive, she kicks his ass and kills him off for real.
Alice has a heart attack in one episode. In the next, she's alive and well, but in the episode after, she has another one and is never seen again.
Emperor Evulz dies the first time.
Alice has a heart attack and is never seen again.
"OK, so Emperor Evulz has a lot of fans who would get pissed if he died. But Alice is The Hero and she has to win. Wait, I've got it..".
Alice is the protagonist of the series, so it's impossible to kill her off after a heart attack.
"I know you thought I was dead, but that's why pencils have erasers!"
Bob: "How did you survive that heart attack?" Alice: "That's the way the cookie crumbles!"
Emperor Evulz decides to goad Alice into throwing him into the ocean so he can live to fight another day.
Alice has a heart attack in one episode. In the next, she wakes up in the coffin confused about what's going on.
Emperor Evulz can't afford Alice disrupting the operations in his stronghold, so he faces her at a different location and "dies" so she'll believe her quest is done. While he recovers, business continues as usual.
Alice has a heart attack in one episode. In the next, she feels better.
Alice, not entirely sure that Evulz is dead, decides to go make sure.
Alice has a heart attack in one episode. Bob pokes her with a stick. Alice tells him to bog off.
"I don't know...I know I just killed Evulz, but I have this incredibly odd feeling in the back of my mind that he's just going to show up again to fight me".
"Alice? What about the heart attack?"
"Ah, I know how this thing ends. Right after they begin their celebration party for finally having killed the bad guy, he's gonna show up, ready and raring for Round Two".